Investigations are being conducted on the experimental neuropathology of the optic nerve and chiasm. Using rats, the lesions produced by ethambutol are being characterized. Study techniques include light and electron microscopy and histochemistry. Studies of the lesions of monoamine oxidase inhibitor intoxication are being initiated. BIBLIOGRAPHIC REFERENCE: Lessell, S., and Miller, J.R.: Optic Nerve and Retina after Experimental Circulatory Arrest. Investigative Opthalmology 13:748-756, 1974.